George miller



@i jm@ Siam-ewfdaf GEORGE MILLER, OF MELBOURNE, VICTORIA, EXEGUTOR 0F THE ESTATE` 0F JAMES F. MCKENZIE, DEGEASED. Letters Patent No. 72,216, dated Decentbe1'-17, 1867.

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TO ALL WHOM IT MAY CONCERN Be it known that J. FARQUHARSON McKENZIn, of Melbourne, in the British colony of Victoria, invented a v new and useful Improvement in Generating and Superheating Steam; and I dohereby declaro thatvthe following is a full, clear, and exact clescriptiori thereof, which will enable others skilled -Ain the art to .make and use the same, reference being had to the accompanying drawings, forming part of this specification.

This invention relates to the manner in which steam is generated and superheated, and to the means by which the pressure of the steam is regulated, and also to the manner in which .the temperature is controlled; and the invention consists in providing, in connection with a furnace or hre-box, generating-pipes or tubes,

wherein the water enters and is converted into steam, and also snperheated, which are surrounded by theU products of combustion for that purpose; and in providing means for regulating the supply of water admitted into the generating-tubes by the temperature of the steam,l and in regulating the combustion of fuel in the furnace by the damper in the chimney, or controlling the 're by the pressure of steam, as will be hereinafter described.

Figure 1 represents a vertical section ofthe furnace, showing the position of the generating-tubes and the damper in the chimney. i

Figure 2 represents thefurnace and the generating and superheatingdevice, with the arrangement of the thermostadt, by which the supply of water is regulated; and also the loaded plunger, which regulates the damper by the pressure of the steam also, a view of the safetyfvalve and steam-pipe.

Figure 3 is a plan or top view of the furnace and tubes. l

Figure 4 is a detached view of the generating and superheating-tube, with the thermostadt attached.

Similar letters of' reference indicate like parts, y f l i A represents the walls ofV a suitable furnace-arch, in which .the 'generating and superheating of the steam are accomplished. B represents the generating and superheating-tubes, which are surrounded by the 'products of combustion. C, iig. 4, is the thermostadt. D is the water-supply pipe. E is the damperregulator. F is the safety-valve.

Fol-.convenience of description, the generating 'and superheating-tubes are detached, and represented as a straight tube, and seein separated from vthe furnace in ligs. 2 and 4. The divisions represented in these detached views by 1, 2, 3, 4, and 5, are designed to represent the dilerent tubes, a top view of which is seen in g. 3; and the small apertures, from one division to the other, denote the aperture through the bend at the ends of the tubes where they are'connected,as at a, gl. The number of these tubes for generating and superheating steam maybe increased to suit-the power required, but it would be necessary to have a thermostadt for each tube. All the tubes would discharge'intp a common steam-chamber, but be suppliedwith water separately.

In describing g. 2, and the parts connected with it, and the detached pipe, we shall describel all the essential portions of the apparatus. The intention is to have a stream or current of water and steam passing through the pipe at a constant rate, as regards quantity, when the engine is running regularly, and to have the quantity of water regulated by thc temperature, through thc thermostadt, placed in the tube which operates a valvein thel water-pipe, and also that the steam shall be discharged into the steam-chamber, where the pressure operates upon arpiston or plunger, and thereby turns or governs the damper in the chimney. G represents the steam-chamber. H is the steam-pipe to the engine.V .The spindle of the thermostadt is seen at e, figs. 2 and 4.

d. is a rod connected with the spindle, which operates the valve through the lever f. The thcrmostadt is composed of plates, or strips of iron and brass riveted together, and coiled round the spindle, and-connected with the spindle in such a manner that the difference in the contraction and expansion of the metals composing the thermostadt produces a partial revolutionin the spindle, and in that way it operates upon the valve t in the water-pipe, through the rod and lever already described. Should the temperature rise above a certain height,

say 450,the thermostadt would open the valve and let in water faster than. it would be continued at that tem- -perature; and on the other hand, should the temperature fall below, say 350", the thermostadt would shut ot the supply of water. In passing from Vone division of the tube to another, after entering the first one, the water is converted into steam, and the steam is raised in temperature as it progresses towards the thermostadt. As before stated, the fire is regulated through the rod E, operating on the damper, by the pressure ofthe stearntin the chamber G. K is a weight on the rod E, which ,should bear upon the rod with a force equal to the required pressure of steam. m is an arm attached to the rod E, and to the damper-rod. The damper is seen in fig. 1l, at u.

In examining the action of the generator, the fact must not be overlooked that the water cannot pass faster out of any tube or compartment than it is admitted into it. The great peculiarit-y of this generator is, that it renders practicable the Working of the pressureof superheated steam, and its temperature, as two independent quantities. The pressure, which is the measure of power, regulates the combustion in the furnace, and the temperature regulates the quantity of water introduced. T he increase of all matter from a lower to a higher temperature is power, and the measure of that power is the'prcssure of an expansive agent. 1

One great diieulty in using superheated steam hitherto has been its iluctuations of temperature, and impossibility ef controlling them.- It is imperative that, in using it, the engine-cylinder be kept at nearly a constant temperature; otherwise the expansions and contractions due to the variations soon destroy both piston and cylinder, and render it impossible to keep them steam-tight.

This system of werking superheated steam can be pursued with perfectsafety, as there would be too small a quantity of water or steam in a single tube to'make an explosion dangerous. There being ne large body'of water to heat up, and the generating and superheating of the steam being almost instantaneous and constant, a great savingin both fuel and time Vwould be the result. When compared with the ordinary steam-boiler, the advantages gained in `point of eheapness, lightness, or portability, and the facilities afforded for repairs, or'for increasing the size or power of the boiler, must be obvious to all engineers and others at all acquainted with the subject.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The generating and superheating-tube B, constructed as described in sections, the points oi' connection of each section provided with an inner disk, having a central opening, as herein set forth.

2."`The tubes B, constructed as described, in combination with the thormostadt, one or more, and arranged in the furnace, as herein set forth and represented.

The above specification of my invention signed by me, this twenty-sixth day of' October, 1866.

GEORGE MILLER, Sole Eirecfutor and Legal Representative of James Farqu/zarson M'cKenze.

Witnesses:

WM. AnAMsoN, EDWD WATERS. 

